Because of costs, use of very thin wall pipe, formed from flexible polymeric material, has become common in drip irrigation systems for the drip tubes, this thin wall pipe itself being connected to a sub-main (or a main) pipe which is often a pipe also formed from a flexible polymeric material which, except when in use, has two opposite walls contiguous with one another so that it lays flat. The drip tube is also similarly arranged, but of course much smaller in size.